| PVPANIC DEVICE |
| ============== |
| |
| pvpanic device is a simulated ISA device, through which a guest panic |
| event is sent to qemu, and a QMP event is generated. This allows |
| management apps (e.g. libvirt) to be notified and respond to the event. |
| |
| The management app has the option of waiting for GUEST_PANICKED events, |
| and/or polling for guest-panicked RunState, to learn when the pvpanic |
| device has fired a panic event. |
| |
| ISA Interface |
| ------------- |
| |
| pvpanic exposes a single I/O port, by default 0x505. On read, the bits |
| recognized by the device are set. Software should ignore bits it doesn't |
| recognize. On write, the bits not recognized by the device are ignored. |
| Software should set only bits both itself and the device recognize. |
| Currently, only bit 0 is recognized, setting it indicates a guest panic |
| has happened. |
| |
| ACPI Interface |
| -------------- |
| |
| pvpanic device is defined with ACPI ID "QEMU0001". Custom methods: |
| |
| RDPT: To determine whether guest panic notification is supported. |
| Arguments: None |
| Return: Returns a byte, bit 0 set to indicate guest panic |
| notification is supported. Other bits are reserved and |
| should be ignored. |
| |
| WRPT: To send a guest panic event |
| Arguments: Arg0 is a byte, with bit 0 set to indicate guest panic has |
| happened. Other bits are reserved and should be cleared. |
| Return: None |
| |
| The ACPI device will automatically refer to the right port in case it |
| is modified. |
